<script>
    /* 
        \n换行

        toString()
        String()

    
    */
   var abcd = 'abcd';
//    重新销毁 
var a = 10;
console.log(a.toString());
console.log([]=={});
console.log([]==={});
console.log([].valueOf());
console.log([].valueOf().toString());
console.log({}.valueOf());
console.log({}.valueOf().toString());//object,object
</script>